The exemplary embodiments relate to the formation of copper interconnects in semiconductor devices and, more particularly, relate to the formation of copper interconnects in semiconductor devices by the use of a sacrificial layer to protect an underlying seed layer.
As the size of semiconductor devices shrink, it becomes more difficult to fill the trench/via gaps with copper by electroplating of copper in the damascene copper interconnect formation process. In order to improve the copper gap filling performance by electroplating, a seed enhancement layer may be applied underneath the copper seed layer. As the semiconductor device dimension becomes smaller and smaller, the use of a copper seed layer on top of the seed enhancement layer may no longer be possible because of the pinch off of the copper seed layer at the entrance of the trench/via. This pinch off makes it difficult to fill the gap with copper without voids in the features by copper electroplating.